CN1068704C

CN1068704C - Method for pre-stressing CRT tension mask material

Info

Publication number: CN1068704C
Application number: CN96195020A
Authority: CN
Inventors: 理查德·W·诺斯克
Original assignee: RCA Licensing Corp
Current assignee: RCA Licensing Corp
Priority date: 1995-06-26
Filing date: 1996-06-04
Publication date: 2001-07-18
Anticipated expiration: 2016-06-04
Also published as: WO1997001860A1; AU6148796A; TW298655B; JPH11508395A; JP3704156B2; US5509842A; CN1189239A; KR100440043B1; DE19681458C2; MX9710524A; MY112324A; KR19990028292A; DE19681458T1

Abstract

The present invention relates to a method for pre-stressing the CRT tension mask (24) to induce creep. The method includes the steps of applying a suitable force to the mask material to induce stress therein; heating the mask material to an ultimate temperature, for a sufficient time, while under stress, to induce creep; and cooling the material.

Description

The method of pre-stressing CRT tension mask material

The present invention relates to the method that a kind of preparation is used for the tension mask material of cathode ray tube (CRT), more particularly relate to before material for shadow mask is loaded into CRT pre-stretching CRT tension mask material to produce the method for creep.

Shadow mask or tension mask are the parts of CRT face board component, and it is near the phosphor screen setting that forms on the inner surface of seeing the screen plate.As known in the CRT technical field, shadow mask plays color selective electrode or parallax-barrier layer, and each bundle in three electron beams that it guarantees to be produced by the electron gun in the neck that is arranged on CRT only bump is its specified phosphor deposition district.The conventional curved surface shadow mask of La Shening is not supported in the framework usually, and this frame fixation is in fluorescence panel.Typical case is that conventional shadow mask has the thickness of about 0.15mm (6 mil), and the heart partly has the transmissivity of about 18-20% therein.A kind of single-axle tension shadow mask has parallel grid unit, these unit only extend in one direction and are spaced laterally apart mutually with the lateral separation identical with conventional shadow mask, this single-axle tension shadow mask has intrinsic high transmittance, because it does not have horizontal intercell connector.Authorize on January 25th, 1972 among people's such as Tachikawa the U.S. Pat P 3638063 and described a kind of such shadow mask.Disclosed this tension mask is to be that 0.5mm (19.7 mil) and thickness are that the grid unit of 0.1mm (3.9 mil) constitutes by width.The problem that tension mask exists is, in CRT manufacturing operation process, when for example adopting frit panel to be sealed on the cone of CRT glass bulb under about 435 ℃ or higher sealing temperature, grizzly bar can permanently expand.For preventing that the bending of this expansion rear grid strip is taking place, conventional method provides enough framework compliances, even so that after the grizzly bar elongation, also can keep required tension force on grizzly bar in the sealing-in operating process.But, according to being the selected material of grizzly bar and frame parts, grizzly bar may produce degree like this when the frit sealing-in elongation is so that in the course of normal operation of cathode ray tube, the framework compliance that may be difficult to provide enough is kept tension force required on the grizzly bar.

Authorize the corresponding European patent application EP-A-0393488 of people (Sony company) U.S. Pat-A-5111107 such as Kume with on May 5th, 1992 this problem has been proposed following solution: the metallicity parts are installed on the opposed surface of elastic support member, elastic support member is installed between the support stick that constitutes framework, and is positioned at the opposition side of the grid unit that is mounted to framework.The metallicity parts have the thermal coefficient of expansion bigger than elastic support member.Therefore the structure of framework is improved.

Therefore, wished before tension mask is mounted on the fluorescence panel of CRT, the pre-stretching grizzly bar, to produce permanent strain or the elongation relevant with the time of the material that is caused by stress, the back is referred to as creep.

The purpose of this invention is to provide a kind of pre-stretching CRT tension mask material to produce the method for creep.This method may further comprise the steps: material for shadow mask is applied suitable power, to produce stress therein; Under described stress, heating material for shadow mask to a limiting temperature also keeps adequate time, to produce creep; With the cooling material for shadow mask.

Fig. 1 is the plane graph that embodies color CRT of the present invention, and wherein part is axial cutaway view.

Fig. 2 is the plane graph of the shadow mask-frame assembly with tension force that is used for the CRT of Fig. 1.

Fig. 3 is the front view of the shadow mask-frame assembly that obtains of the line 3-3 along Fig. 2.

Fig. 4 is a kind of end view of device of pre-stretching CRT tension mask material.

Fig. 5 is the top view of this device of obtaining of the line 5-5 along Fig. 4.

Fig. 6 be the device of Fig. 4 be placed in have controlled atmosphere stove in the time end view.

Fig. 1 illustrates a cathode ray tube 10, and it has a glass bulb 11, and this glass bulb comprises the neck 14 of 12 and pipe shapes of fluorescence panel (faceplate panel) of a rectangle, and fluorescence panel 12 is connected with the cone 15 of neck 14 by a rectangle.Cone has an internal conductive coating (not shown), and this coating extends to neck 14 from anode button (anode button) 16.Panel (panel) 12 comprises the 18 and peripheral edges of sight screen plate (faceplate) or the sidewall 20 of a cylinder shape, and the latter is sealed to cone 15 by frit 17.Tricolour phosphor screen 22 is by the inner surface carrying of screen board 18.Phosphor screen 22 is line-screens, and it has the phosphor strip of arranging in three colour cell modes, and each three colour cell comprises each the phosphor strip in corresponding three kinds of colors.The porous color selection electrode of a cylinder shape or tension force (tension) shadow mask 24 is installed in the panel 12 in the mode that can remove, and with respect to phosphor screen 22 predetermined spacing is arranged.An electron gun 26 that is simply illustrated by dotted line in Fig. 1 medially is installed in the neck 14, be used to produce the electron beam that three in-lines are arranged, be center electron beam and two sides or outer beams, and make these three electron beams arrive phosphor screens 22 by shadow mask 24 along convergence path.

The CRT of Fig. 1 will with an external magnetic deflection yoke coupling, the deflecting coil 30 shown in for example contiguous cone-neck intersection.When being energized, deflecting coil 30 makes three electron beams be subjected to the effect in magnetic field, makes electron beam scan a level and vertical rectangular grating on phosphor screen 22.As shown in Figure 2, tension mask 24 is tension masks of a single shaft, and it is preferably made by the thick mild-steel sheet of about 0.05mm (2 mil) of a rectangle, and it comprises two long limits and two minor faces.Two long limits of shadow mask are parallel to the central longitudinal axis X of shadow mask, and two minor faces are parallel to the central minor axis Y of shadow mask.This shadow mask comprises a porose part, and this part comprises a plurality of elongate strip 32, and these are separated by a plurality of slits 33, and slit 33 is parallel to the minor axis of shadow mask.Each slit 33 extends to another the long limit near shadow mask outside a close long limit of shadow mask.At framework 34 that is used for this tension mask shown in Fig. 1-3, this framework comprises four critical pieces, i.e. two torque tubes (torsion tube) or bending part 35 and 36 and two tension arms or straight parts 38 and 40.Two bending parts 35 and 36 are parallel to major axis X and parallel to each other.As shown in Figure 3, each

straight parts

38 and 40 comprises two half overlapping parts or

part

42 and 44, and each part has a L shaped section.Overlapping

part

42 and 44 welds together at its overlapping.Each part 42 and an end of 44 are connected to an end of one of bending part 35 and 36.Bending part 35 and 36 curvature and the cylindrical curvature of tension mask 24 are complementary.The long limit of single-axle tension shadow mask 24 is welded between two bending parts 35 and 36, and they provide shadow mask 24 required tension force.

Adopting frit fluorescence panel 12 to be sealed in the process of cone 15, for minimum degree is reduced in the secondary creep that makes tension mask, single-axle tension shadow mask 24 adopts device 50 pre-stretchings shown in the Figure 4 and 5.This device 50 comprises a support 52, second first type surface 56 that this support has first first type surface 54 and is oppositely arranged.A backstop boss (boss) 58 is located on first first type surface 54 of support 52, and extends on this surface, as described later.Main folder tool 60 with first jaw 62 is spaced apart with backstop boss 58, and with first first type surface 54 of support 52 be one or the one end be fixed to first first type surface 54 of support 52.Main folder tool 60 also comprises second an adjustable jaw 64, this second jaw by main fixed part 65 for example screw or bolt link to each other with first jaw 62, it can be regulated, so that tension mask material is clamped between first and second jaws 62 and 64.One movably auxiliary clamp 70 be arranged near the backstop boss 58.Auxiliary clamp 70 comprises one the 3rd jaw 72, and this jaw is fixed to an axostylus axostyle 74.Axostylus axostyle 74 has a near-end 76 and a far-end 80, and near-end 76 is arranged in the cam 78, and far-end 80 extends through an elongated hole 82, and this elongated hole is formed in the pillar 84, and pillar 84 is fixed on the support 52.Extend in the plane of first first type surface 54 that is parallel to support in hole 82.Auxiliary clamp 70 also comprises the 4th an adjustable jaw 86, for example screw or bolt link to each other with the 3rd jaw 72 this 4th jaw by auxiliary retention portion part 88, it also can be regulated, so that tension mask material is clamped between third and fourth jaw 72 and 86.Cam 78 has a backstop boss matching surface 90, the flat cam contact surface 92 of its contactor banking stop boss 58.A rod arm (lever arm) 93 has a near-end 94, and this near-end is for example by being welded and fixed to a side of cam 78.The far-end 96 of rod arm 93 comprises a recess 98, and this recess supports a pouring weight 100, and this pouring weight applies simple stress to material for shadow mask.As shown in Figure 5, device 50 is designed for after slit 33 (preferably) runs through formation by etching, makes tension mask 24 pre-stretching equably.Another kind of mode is, can be before slit 33 forms the section (section) of tensile stress material for shadow mask, perhaps, if shadow mask forms by a plurality of are wound on the axle, rather than form by etching material for shadow mask thin plate, can adopt similar each bonding jumper of device pre-stretching.Refer again to Fig. 5, cam 78 can comprise the cam of two separation, and these two cams are near each side of first surface 54, and in this case, the backstop boss 58 of separation is arranged near each cam.Cam 78 provides 11.5: 1 extensibility (pull ratio) on material for shadow mask.Be applied to stress value on the material and be by the quality decision of the pouring weight 100 that is adopted.

Width is that 0.3mm (12 mil), thickness are the long bar of a 381mm (15 inches) of the tension mask material of 0.05mm (2 mil), do not adopt pre-stretching method of the present invention described herein during manufacturing, and under 440 ℃ of temperature, be heated 1 hour, when the stress that applies is 703kg cm ^-2(10 ⁴Psi) time, produced the creep of 0.43mm (17 mil).When stress is increased to 1406kg cm ^-2(2 * 10 ⁴Psi) time, creep compliance increases to 1.4mm (55 mil).Yet the bar of an identical shadow masks material is at 1406kg cm ^-2Pre-stretching is 1 hour under (stress) and the 470 ℃ of temperature, then at 703kg cm ^-2Stress and 440 ℃ temperature under handle through 1 hour, this processing of back is near frit sealing-in condition, the result does not produce additional creep.But, if under 440 ℃ temperature through 1 hour, stress is increased to 1406kgcm ^-2, creep compliance increases to 0.43mm (17 mil).

In order further to reduce the creep in the frit sealing-in process, be higher than actually and implement preferred pre-stretching method under the temperature of frit sealing temperature.In this method for optimizing, tension mask 24 is placed in main folder tool 60 and movably between the auxiliary clamp 70, and is fixed on therebetween by fixed part 65 and 88.Be applied to the far-end 96 of rod arm 93 by pouring weight, on clamped tension mask 24, produce about 1547kg cm 12.3kg (27.1lb) ^-2(2.2 * 10 ⁴Psi) stress.Then, this device 50 is loaded into a stove 102, and as shown in Figure 6, this stove comprises a suitable gas mixer 104, and this blender provides the weak oxide of being made up of the oxygen of most of nitrogen and several percentages atmosphere in stove.Representative condition is, nitrogen accounts for about 96wt.% (weight %) of atmosphere in the stove, and oxygen accounts for about 4wt.%.Flow regulator 106 and 108 is controlled the amount of oxygen and nitrogen respectively.The temperature of stove 102 is elevated to 500 ℃ with about 10 ℃/minute speed, and keeps about 1 hour under this temperature.Subsequently, material for shadow mask is cooled to room temperature (about 22 ℃).In fact 500 ℃ of temperature that are higher than about 460 ℃ frit sealing temperature are allowed the about 2.515mm of the average creep of material for shadow mask bar (99 mil) that this 381mm is long.The weak oxide atmosphere that adopts in the prestretching process of material for shadow mask also makes shadow mask melanism in pre-stretching technology, thereby has reduced its reflection, has improved the fluoroscopic contrast of CRT thus.

The preferred mild steel that is used to form tension mask 24 has such component by weight: about 0.005% carbon, 0.01% silicon, 0.12% phosphorus, 0.43% manganese and 0.007% sulphur.ASTM (ASTM) granularity is preferably in 9 to 10 scopes.The pre-stretching of the material for shadow mask that this method for optimizing according to the present invention is implemented is considered to make the material for shadow mask excess load, thereby under the stress that is applied, the diffuse that is activated in the shadow mask is to its granule boundary.This makes material unlikely further creep in frit sealing-in process.When at 1406kg/cm ^-2(2 * 10 ⁴When keeping 1 hour under the frit sealing temperature condition of tensile stress psi) and 460 ℃, the tension mask of handling by method described herein has produced the only secondary creep of 0.05mm (2 mil).Even by long frit (sealing-in) operating process of the material for shadow mask of method pre-stretching described herein experience, wherein temperature slowly was increased to 460 ℃ and kept 1 hour under this temperature in 7 hours, and creep also only is additional 0.05mm (2 mil).This little additional elongation amount can be compensated by the compliance of shadow mask frame, and can not have problems for the shadow mask of handling by this new method.

Claims

1. a pre-stretching CRT tension mask material may further comprise the steps to produce the method for creep:

A) with the single shaft direction described material for shadow mask is applied suitable power, to produce tensile stress in described single shaft direction;

B) described material for shadow mask is heated to a temperature that raises, this temperature is higher than any processing temperature that CRT stands described in the manufacture process, and keeps adequate time under tensile stress, to produce creep; With

C) the described material for shadow mask of cooling is to room temperature.

2. implement heating steps b in a kind of weak oxide atmosphere according to the process of claim 1 wherein also to be included in) so that on the surface of described material for shadow mask, form an oxide layer.

3. according to the method for claim 1 or 2, wherein said power produces about 1547kg cm ^-2Tensile stress.

4. according to the method for claim 1 or 2, wherein, the temperature of described rising is about 500 ℃.

5. according to the method for claim 1 or 2, wherein, the described sufficient time is about 1 hour.